Bull fighting is a traditional spectable for many Spaniards, but it is considered by some as cruel and distasteful and not a sight for the faint hearted.

No matter how you feel about it, be warned that you will see a lot of blood.

But if after all you decide to go, try to not behave "as a tourist" when you're there (making loud comments, covering your eyes with your hands or obviously expressing your dissatisfaction by what you're seeing). If you don't understand why people clap, shouts, or says "olé" at a given moment just keep a low profile... or follow the crowd.

Spain - Bullfight Info

Some suggestions about attending a bullfight can be found here.